The synthesis of inherently conducting polymers (ICPs) has become an appealing area of research since the discovery of electrically conducting conjugated polymers.
Polyaniline (PANi) is an ICP that has been widely explored because it is relatively cheap and easy to synthesize. The applications of polyaniline (PANi) are of great interest to many fields. A disadvantage in the use of polyaniline is the insolubility of the emeraldine salt in water as well as most organic solvents.
Polyaniline grafted lignosulfonic acid (Ligno-PANi) is a water-dispersible inherently conductive polymer, such as disclosed in U.S. Pat. Nos. 5,968,417; 6,059,999; and 6,299,800, the disclosures of which are incorporated by reference herein.
Ligno-PANi is one of the only dispersible polyanilines commercially available on a mass scale, presently commercially available from PolyOne Corporation from Avon Lake, Ohio (www.polyone.com). The high solubility of the lignosulfonate counter ion leads to a dispersible product.
Because lignin is the second most abundant renewable resource in nature and the fact that lignosulfonates are a waste product of the paper industry, the synthesis of Ligno-PANi is environmentally friendly.
It is known that the incorporation of dopants to achieve higher conductivities in addition to lignosulfonates during the polymerization process results in prohibitively long initiation times.